\(\left(9x^2-12x+4\right)-\left(y+2\right)^2\)
\(=\left[\left(3x^2\right)-2.3x.2+2^2\right]-\left(y+2\right)^2\)
\(=\left(3x-2\right)^2-\left(y+2\right)^2\)
\(\left(9x^2-12x+4\right)-\left(y+2\right)^2\)
= \(9x^2-12x+4-\left(y^2+4y+4\right)\)
=\(9x^2-12x+4-y^2-4y-4\)
=\(9x^2-y^2-12x-4y\)
=\(\left(3x-y\right)\left(3x+y\right)-4\left(3x+y\right)\)
=\(\left(3x+y\right)\left(3x-y-4\right)\)
( 9x2 - 12x + 4 ) - ( y + 2 )2
= [ (3x)2 - 2.3x.2 + 22 ] - ( y + 2 )2
= ( 3x - 2 )2 - ( y + 2 )2
= [ ( 3x - 2 ) - ( y + 2 ) ][ ( 3x - 2 ) + ( y + 2 ) ]
= [ 3x - 2 - y - 2 ][ 3x - 2 + y + 2 ]
= [ 3x - y - 4 ][ 3x + y ]